Effectiveness, Safety, and Tolerability of Bilastine Up-Dosing in Chronic Spontaneous Urticaria Uncontrolled with Licensed Doses of Other Second-Generation Antihistamines—An Institution-Based, Open-Label, Single-Group Longitudinal Trial

BACKGROUND: Bilastine 20 mg daily is a second-generation antihistamine (sgAH) approved for chronic spontaneous urticaria (CSU). Up-dosing to 40 or 80 mg daily is recommended in uncontrolled patients. AIM AND OBJECTIVES: Evaluating the effectiveness, safety, and tolerability of bilastine at 20, 40, and 80 mg daily in CSU patients uncontrolled with licensed doses of other sgAHs. PATIENTS AND METHODS: In this institution-based, open-label, longitudinal trial, CSU patients were evaluated for demography, angioedema, and symptomatic dermographism. Urticaria disease severity was assessed by urticaria activity score (UAS7) score on days 0, 14, 28, and 42. All patients received bilastine 20 mg daily for two weeks. Non-responders (UAS7 > 0) were up-dosed to 40 or 80 mg. Laboratory tests were conducted at baseline and on day 42. RESULTS: Thirty-five CSU patients (mean age 34.5 years, median duration six months) were included. Bilastine 20 mg reduced mean UAS7 score from 25.7 to 6 at day 14 ( P < 0.001), with 16 achieving complete resolution (UAS7 = 0). Among non-responders, up-dosing to 40 mg further reduced UAS7 to 1.9 ( P < 0.001), with 15 more patients achieving UAS7 = 0. Only four required 80 mg, showing minimal additional benefit. ( P = 0.1). Overall, 94% achieved complete control. Somnolence (22%) and headache (50%) occurred at higher doses, but with good tolerability. A higher baseline UAS7 score increased the odds for up-dosing (OR 1.2, P = 0.001). LIMITATIONS: Our study is limited by its small sample size, single-center design, and absence of a control group. Additionally, lack of information on prior antihistamine use or compliance may have confounded the assessment of refractoriness. CONCLUSION: Up-dosing of bilastine is effective, safe, and tolerable in CSU patients uncontrolled with licensed doses of other sgAHs. Almost 90% patients responded to 20-40 mg, while 80 mg did not show a significant additional benefit. A higher baseline UAS7 score may indicate the need for up-dosing.